The equation x^2 -4x-8=0 has a solution between 5 and 6. Find a solution to this equation to 1 decimal place. How do I do this?

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Answer 1 · 2018-05-25T11:18:45

x=5.5 or -1.5

use #x=[-b\pmsqrt(b^2-4xxaxxc)]/(2a)# where a=1, b=-4 and c=-8

#x=[4\pmsqrt((-4)^2-4xx1xx-8)]/(2xx1)#

#x=[4\pmsqrt(16+32)]/(2)#

#x=[4\pmsqrt(48)]/(2)#

#x=[4\pm4sqrt(3)]/(2)#

#x=2+2sqrt3 or x=2-2sqrt3#

x=5.464101615 or x=-1.464101615